- 1 Type about:config into the Firefox address bar followed by <enter>. You will get a warning but just accept the risk.
2 You should get a list of preference names with each one followed by its settings. Above the list should be a search bar.
3 Type browser.tabs.remote.autostart into the search bar bar.
4 That should reduce the list to two items, browser.tabs.remote.autostart and browser.tabs.remote.autostart2.
5 Make sure these are both set to false. On mine the first one was set to false and the second was set to true. If either is set to true change the setting to false by clicking on it until it changes.
6 Close the tab and restart Firefox.
Hopefully the crashes will end.
PS Note that it is a colon in the first command not a full stop.